Aerial and ground photographic equipment for photographing nuclear bomb explosions with automatically controlled interval filter and aperture settings



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3 Sheets-Sheet 1 G. w. GoDDARD 2,998, AERIAL AND GROUND PHOTOGRAPHICEQUIPMENT FOR PHOTOGRAPHING Sept. `5, 1961 NUCLEAR BOMB EXPLOSIONS WITHAUTOMATICALLY CONTROLLED INTERVAL FILTER AND APERTURE SETTINGS FiledAug. 20, 1956 R. mm mw vw me v w. m E GY B H TTOENE YJ' Sept. 5, 1961 G.w. GODDARD AERIAL AND GROUND PRUTOGRAPHIC EQUIPMENT FoR RROTUGRAPHINGNUCLEAR BOMB ExPLosIoNs wITR AUTOMATIUALLY coNTRoLLED INTERVAL FILTERAND APERTURE SETTINGS 3 Sheets-Sheet 2 Filed Aug. 20, 1956 INVENTOR.

GEoReE w. sonpnno Sept. 5, 1961 G. w. GODDARD AERIAL AND GROUNDPHOTOGRAPHIC EQUIPMENT FOR PHOTOGRAPHING.

NUCLEAR BOMB EXPLOSIONS WITH AUTOMATICALLY CONTROLLED INTERVAL FILTERAND APERTURE SETTINGS 3 Sheets-Sheet 3 Filed Aug. 20. 1956 M9050 Ok un Mtulo mm INVENTOR 6604366 M Gobo/'a fwwg@ A ITOQNEYS United States PatentO 2,998,762 AERIAL AND GROUND PHOTOGRAPHIC EQUIP- MENT FOR PHOTOGRAPHlNGNUCLEAR BOMB EXPLOSIONS WITH AUTOMATICALLY CON- TROLLED INTERVAL FILTERAND APERTURE SETTINGS George W. Goddard, Chevy Chase, Md., assgnor toBulova Research and Development Laboratories, Inc., Woodside, N.Y., acorporation of New York Filed Aug. 20, 1956, Ser. No. `605,051 Claims.(Cl. 95-12.5)

The present invention relates generally to military photography and moreparticularly to photographic apparatus Aadapted to automatically recordnuclear bomb explosions prior to the formation of a shock Wave cloud.

In previous warfare, strike assessment photography was carried out bymeans of cameras installed either Within the bombing aircraft or inother aircraft involved in that same mission. Bomb damage assessment wasusually accomplished some time after the bombing mission, when theatmosphere had cleared suiiciently to provide -a reasonably clear Viewof the target area. By comparison to nuclear bombs, the heaviest ofexplosives used during World War Il were distinctly localized in theirdestructive effects, characteristic of relatively short destructiveradius. Large area bombing was effected by use of many aircraft pertarget, each loaded with many bombs, and used in salvo or stick drop inan effort to build up the destructive radius.

Within the scope of the strategic mission it was then still possible toperform the photographic recording of the effects of the strike. Detailbomb damage assessment (BDA), which followed subsequently, involvedphotography of the target areas at rather substantial photographic scale(1:10,000 or greater) in an eiort to provide ground detail at an imagescale adequate for accurate and rapid interpretation.

The new nuclear environment is capable of measuring the destructiveradius, not in terms of yards but in miles. In addition to thetremendous increase in lethal radius of nuclear weapons, the nature ofthe after-effects of such detonations renders the skies, in the vicinityof the bombed area, untenable for use of conventional strike and bombdamage assessment techniques. Modern aircraft vehicles have providedsubstantial gains in speed range and altitude capabilities, consonantwith this new environment. On the other hand, photographic techniqueshave not kept abreast of the recording requirements for the modernmission.

Accordingly, the principal object of this invention is to provide afully automatic photographic system adapted to record nuclearexplosions, the operation of the system being integrated with the bombdrop procedure.

More particularly, the object of this invention is to provide aphotographic system for aerial or ground installations havingautomatically controlled interval filter and aperture settings. It ispossible with the invention, using a single camera, to photographcompletely all sequences of a nuclear explosion with the correctcombination of exposure iilters and aperture settings.

EFor a better understanding of the invention as well as other objectsand further features thereof, reference is had to the following detaileddescription to be read in connection with the accompanying drawingwherein:

FIG. 1 is a cross-sectional view of a camera system in accordance withthe invention.

FIG. 2 is a sketch illustrative of the location and relationship of thevarious components involved to produce the operating cycle inlaccordance with the invention.

FIG. 3 is a schematic diagram illustrative of the operation of thecamera system.

Referring now to FIG. l, there is shown an aerial ICC camera, generallydesignated by numeral 10, which is mounted on suitable trunnions 11,whereby the camera may be angularly oriented, as desired.

The camera is normally mounted in an aft position on the aircraft suchthat the lens field angle is that of a high, rear shooting oblique. A 6inch focal length metrogon lens will, in such location provide a fieldcoverage of some 74 both horizontally and vertically. This wide anglecoverage will amply cover the field which includes the impact point,despite angular positional changes that the bombing aircraft may make inevasive maneuvers following the bomb drop.

It is to be understood that while an aerial installation is describedherein by way of illustration, the invention is lalso applicable toground photographic installations.

The camera includes a program timer 1.2 which acts to control a cycle ofoperations. The aerial system is initiated by means of a pulse or othercontrol signal from the bomb release mechanism on the plane, which inturn triggers the camera program timer 12. The lens port of the camerais covered by a heavy density optical filter 13 mounted on a rocker arm14 which is pivotally coupled by a link member 15 to the armature of asolenoid 16, such that when the solenoid is energized the filter 13 israised, as indicated in dotted lines, to uncover the lens port.

Also included is an opaque capping plate 17 which closes over the filterassembly, Ithe capping plate being mounted on a rocker arm 18 which ispivotally coupled by a link 19 to a solenoid 20. When solenoid 20 isenergized, the plate 17 is raised to expose the filter, the raisedposition being indicated in dotted lines in the figure. A between thelens shutter mechanism 21 is provided as Well as an automatic aperturecontrol 22.

In operation (note FIG. 3), when the camera program timer 12 istriggered by the bomb release mechanism, the following cycle ofsequential operations is set olf:

(A) The heavy density filter 13 closes over the lens ort. p (B) Theopaque capping plate 17 closes over the filter assembly.

(C) The lter 13, upon closing, trips the lens shutter 21 to its openposition and impresses a bias across the aperture control servo motor,causing it to drive the diaphragm to its minimum aperture position.

(D) The automatic aperture control 22 is at this point held inoperative(override by C).

In practice these operations take place Within a period of two secondsafter bomb release (zero time) and place the photographic system in itsReady position. The timer continues to operate to effect the followingsequence.

Assuming for the moment a sixty second drop time, the program timer 12then at approximately 57 seconds after` the time of bomb release,releases the opaque capping plate -17 which is used merely to preventpre-exposure with shutter in open position. The `dense filter is nowstill in the optical path.

At the time of detonation, the intense liash which precedes the burst issensed by a small photocell assembly 28 in the focal plane area behindthe dense filter 13, with the shutter still in the Open position. Thebomb ash detected by photocell 2S -is applied to a flash .peak sensingunit 29y and then initiates the following cycle of operations:

(l) The signal from peak sensing photocell unit is fed to the timer 12.

(2) The timer releases the shutter 21 thereby completing the irstexposure, at which point the dense filter 13 is removed and automaticaperture control is then governed by ambient light.

(3) The camera continues to operate at a rate of 2 exposures per second.

(4) The automatic aperture control then acts to advcamera drive circuit,with camera ready for the next sequence.

(7) Timer resets and stops.

`The sequential operation of the camera system as described, is fullyautomatic once airborne and completely independent of a need for humanoperators. Prior to actual bomb drop and while aircraft is en route tothe target, conventional overlapping photographs can be made to checkthe course of the aircraft to the target area. The program timer isdesigned for variable settings of the Ready-Operate functions therebyallowing that modicum of flexibility for a variety of missions. l Theseground settings may be accomplished in a manner of seconds prior totake-off, providing thereby a desirable short aircraft ready time.

Variations in altitude, which aiiect the bomb drop time. may be sensedby an aneroid diaphragm device which for increasing altitudeautomatically increases the timer4 the initial flash. The peak iiash ofa nuclear ibomb is estimated to be of one four-thousandth of a secondduration. Light rays from the peakV flash produces the photographicexposure prior'to the formation of a mushroom shock cloud. The straightline path of photography accomplished prior to the formation of themushroom cloud is indicated by dashed line 27. v

While there has been shown what is considered-to be a preferredembodiment 'ofthe invention, it will be manifest that many changes andvmodications may be made therein Without departing from the essentialspirit of the invention. It is intended, therefore, in the annexedclaims to cover all such changes and modifications as fall Within thetrue scope of the invention.

What is claimed is:

1. An automatic control system for a camera adapted to photograph anuclear bomb explosion, said camera including a lens, a shuttertherefor, a heavy-density optical filter adapted to cover the lens, andan opaque capping plate adapted to cover the ilter, said system combprsing a program timer operatively coupled to said lens shutter, saidfilter and said capping plate, means to trigger said timer upon releaseof the bomb to effect a rst preparatory sequence rendering said` cameraready whereby said lens is covered by said lter, said lter is capped bysaid plate and said shutter is open, said program timer then effecting asecond operating sequence commencing a predetermined interval after saidbomb is released whereby said capping plate is removed to eX- pose saidlens through said ilter, and photosensitive and other means responsiveto the peak ash of the bomb 'I'he ground target 23 is .4 explosion torelease the shutter and thereby complete a first exposure.

2. An automatic control system for a camera adapted to photograph anuclear bomb explosion, said camera including a lens, a shuttertherefor, a heavy density optical lilter adapted to cover the lens, andan opaque capping plate adapted to cover the lter, said systemcompr-ising a program timer operatively coupled to said lens shutter,said filter and said capping plate, means to trigger said timer uponrelease of the lbomb to effect a first preparatory sequence renderingsaid camera ready whereby said lens is covered by said lter, said filteris capped by said plate and said shutter is open, said timer then v.ef-

fecting a second operating sequence commencing a predetermined intervalafter said bomb is released whereby said capping plate is removed toexpose said lens through said ilter, means responsive to the peak flashof the bomb explosion to release the shutter land thereby complete airst exposure, said timer subsequently acting to including a programtimer operatively coupled to said lens shutter, said Aiilter and saidcapping device, and means to' initiate operation of said 'timer uponlaunching of a bomb to effect a irst preparatory sequence in whichsaid'lens is masked by said ilte'r, said lter is capped by said deviceand said lens shutter is then caused to open, said program timer beingprovided with a timing mechanism to'eect a second operating sequencecommencing a predetermined interval after said bomb is launched to causeremoval of said capping device to expose said ilter whereby the scene tobe photographed is projected onto said lm through both said lens andsaid filter, and photosensitive means responsive to the peak flash ofthe bomb explosion to effect closure of said lensl shutter therebycompleting a irst exposure.

4. A system as set forth in claim 3 wherein said timer is'providcd withmeans acting at the termination of said operating sequence to removesaid lter from said lens and to reopen said shutter to take a secondexposure without said filter.

5. A systemv as set forth in claim 3 yfurther including an adjustableaperture for said lens and an automatic aperture control mechanismoperatively coupled to said filter to maintain a small aperture duringsaid first exposure when said iilter covers the lens and responsive to xA, said program timer to provide a larger aperture during subsequentexposure when'said lter is removed.

References Cited in the le of this patent UNITED STATES PATENTS UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noy 998,762September 5I 1961 l i Georg-e W Goddard i i It is hereby certified thaterror appears in r,the above numbered patentrequiring correction andthat the said Letters Patent should read as 'corrected below. -v

"Ready-'Operate" read READY-OPERATE =-5 line 23,l for "mannerV' Signedand sealed this 27th day of March 1962.,

(SEAL) At'test':

ERNEST W. SWIDERA DAVID L. LADD Attesting Officer Commissioner ofPatents

